Hello,
You can create a new profile by exporting an existing profile,
then editing it with a text editor, and importing it again.
Cura uploads new profiles to the printer when it (Cura) is restarted.
Make a new material profile for each colour.
The material name and GUID must be unique or Cura won't upload it to the printer.
Here are two examples (warning: not tested!).
Sorry I had to zip them, there are restrictions to the types of files I can attach.
testprofiles.zip